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Private Sale
$15,000 USD

Posted September 12, 2025

Item

Rolex Submariner - LTN Test

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Introduction

While the IWC Ingenieur can trace its origins as far back as 1955, the collection was revamped in a rather significant manner in the 1970s following the popularisation of stainless steel luxury sports watches. Designed by Gerald Genta himself, the new Ingenieur SL was a slim ‘Jumbo-sized’ case much like Genta’s Royal Oak that featured an integrated bracelet. Furthermore, it even featured a bezel with four rivets, much like the Royal Oak’s exposed screws. Eventually, following a period of insufficient sales, IWC decided to launch a smaller variant of the Ingenieur, the ref. 3515, in the mid-80s, which is what we have here. With an emphasis on IWC’s elegant design language, the ref. 3515 utilized design touches such as gold hour markers and hands along with slightly textured dials in a bid to swap the Ingenieur’s tool-watch design with a sophisticated look that echoed IWC's dress watch aesthetic while remaining true to the new Ingenieur. Produced only for a short period of time, the ref. 3515 was well-received while it was in production, and today is a rare variant of the Ingenieur that collectors still love to see.

The Details

Brand

Rolex

Dimensions

40mm

Model

Submariner

Movement

Automatic

Reference

5512

Bracelet

Steel Bracelet

Year

1990

Condition

Excellent

Material

Steel

Included

Watch only

Dial Color

Black

THE DIAL
THE DIAL

With its gold hour markers and hands (which are interestingly designed like pencils, with their lume pips appearing as little erasers), the Ingenieur's subtle crosshatch "graph paper" texture within its gray dial feeds into the Ingenieur's engineer aesthetic.

THE DESIGN
THE DESIGN

In keeping with Gerald Genta's iconic 1970s and 1980s sporty design language, the Ingenieur sported a riveted bezel set on a tonneau-shaped case that both fed into the luxury stainless steel sports watch hype that we are still experiencing today. This example features an integrated leather strap that gives it a dressier aesthetic.

TIMING MACHINE READOUT
TIMING MACHINE READOUT

This reading was taken (crown down) with a ONEOF Accuracy Boutique Edition timing machine at time of cataloging. It is provided as a courtesy only, and shall not be construed as a warranty or guarantee of any kind. Please refer to our terms and conditions of sale for more information.

Condition

The watch is in overall excellent condition. The steel case has some light scratches, with a couple of small nicks on the bezel. The case back shows light surface scratches and retains a legible serial number engraving. The dial and hands are later luminova replacement parts and in near-mint condition. The watch was born with this factory black leather fixed-lug style strap with a steel IWC buckle, both in excellent condition. Please note that the watch ticks at time of cataloging, but timekeeping is poor and a service is recommended.

Our Perspective

Another one of Genta's great designs, the Ingenieur has unfortunately been updated yet again by IWC making vintage pieces like this ref. 3515 all the rarer and more important for collectors to cherish. Due to its timeless aesthetic, this ref. 3515 could easily be strapped onto a wrist and worn right away, as is Genta's design's staying power.

Justin Gruenberg

Co-founder